![Daniel Borkmann](/assets/img/avatar_default.png)
We should get rid of all own SCTP debug printk macros and use the ones that the kernel offers anyway instead. This makes the code more readable and conform to the kernel code, and offers all the features of dynamic debbuging that pr_debug() et al has, such as only turning on/off portions of debug messages at runtime through debugfs. The runtime cost of having CONFIG_DYNAMIC_DEBUG enabled, but none of the debug statements printing, is negligible [1]. If kernel debugging is completly turned off, then these statements will also compile into "empty" functions. While we're at it, we also need to change the Kconfig option as it /now/ only refers to the ifdef'ed code portions in outqueue.c that enable further debugging/tracing of SCTP transaction fields. Also, since SCTP_ASSERT code was enabled with this Kconfig option and has now been removed, we transform those code parts into WARNs resp. where appropriate BUG_ONs so that those bugs can be more easily detected as probably not many people have SCTP debugging permanently turned on. To turn on all SCTP debugging, the following steps are needed: # mount -t debugfs none /sys/kernel/debug # echo -n 'module sctp +p' > /sys/kernel/debug/dynamic_debug/control This can be done more fine-grained on a per file, per line basis and others as described in [2]. [1] https://www.kernel.org/doc/ols/2009/ols2009-pages-39-46.pdf [2] Documentation/dynamic-debug-howto.txt Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
374 lines
9.8 KiB
C
374 lines
9.8 KiB
C
/* SCTP kernel implementation
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* (C) Copyright IBM Corp. 2003, 2004
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*
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* This file is part of the SCTP kernel implementation
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*
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* This file contains the code relating the chunk abstraction.
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*
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* This SCTP implementation is free software;
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* you can redistribute it and/or modify it under the terms of
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* the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This SCTP implementation is distributed in the hope that it
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* will be useful, but WITHOUT ANY WARRANTY; without even the implied
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* ************************
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* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU CC; see the file COPYING. If not, write to
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* the Free Software Foundation, 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*
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* Please send any bug reports or fixes you make to the
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* email address(es):
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* lksctp developers <lksctp-developers@lists.sourceforge.net>
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*
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* Or submit a bug report through the following website:
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* http://www.sf.net/projects/lksctp
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*
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* Written or modified by:
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* Jon Grimm <jgrimm@us.ibm.com>
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* Sridhar Samudrala <sri@us.ibm.com>
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*
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* Any bugs reported given to us we will try to fix... any fixes shared will
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* be incorporated into the next SCTP release.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/net.h>
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#include <linux/inet.h>
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#include <linux/skbuff.h>
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#include <linux/slab.h>
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#include <net/sock.h>
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#include <net/sctp/sctp.h>
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#include <net/sctp/sm.h>
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/* This file is mostly in anticipation of future work, but initially
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* populate with fragment tracking for an outbound message.
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*/
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/* Initialize datamsg from memory. */
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static void sctp_datamsg_init(struct sctp_datamsg *msg)
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{
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atomic_set(&msg->refcnt, 1);
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msg->send_failed = 0;
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msg->send_error = 0;
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msg->can_abandon = 0;
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msg->can_delay = 1;
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msg->expires_at = 0;
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INIT_LIST_HEAD(&msg->chunks);
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}
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/* Allocate and initialize datamsg. */
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static struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp)
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{
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struct sctp_datamsg *msg;
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msg = kmalloc(sizeof(struct sctp_datamsg), gfp);
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if (msg) {
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sctp_datamsg_init(msg);
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SCTP_DBG_OBJCNT_INC(datamsg);
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}
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return msg;
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}
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void sctp_datamsg_free(struct sctp_datamsg *msg)
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{
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struct sctp_chunk *chunk;
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/* This doesn't have to be a _safe vairant because
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* sctp_chunk_free() only drops the refs.
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*/
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list_for_each_entry(chunk, &msg->chunks, frag_list)
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sctp_chunk_free(chunk);
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sctp_datamsg_put(msg);
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}
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/* Final destructruction of datamsg memory. */
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static void sctp_datamsg_destroy(struct sctp_datamsg *msg)
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{
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struct list_head *pos, *temp;
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struct sctp_chunk *chunk;
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struct sctp_sock *sp;
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struct sctp_ulpevent *ev;
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struct sctp_association *asoc = NULL;
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int error = 0, notify;
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/* If we failed, we may need to notify. */
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notify = msg->send_failed ? -1 : 0;
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/* Release all references. */
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list_for_each_safe(pos, temp, &msg->chunks) {
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list_del_init(pos);
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chunk = list_entry(pos, struct sctp_chunk, frag_list);
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/* Check whether we _really_ need to notify. */
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if (notify < 0) {
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asoc = chunk->asoc;
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if (msg->send_error)
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error = msg->send_error;
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else
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error = asoc->outqueue.error;
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sp = sctp_sk(asoc->base.sk);
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notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED,
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&sp->subscribe);
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}
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/* Generate a SEND FAILED event only if enabled. */
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if (notify > 0) {
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int sent;
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if (chunk->has_tsn)
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sent = SCTP_DATA_SENT;
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else
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sent = SCTP_DATA_UNSENT;
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ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent,
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error, GFP_ATOMIC);
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if (ev)
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sctp_ulpq_tail_event(&asoc->ulpq, ev);
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}
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sctp_chunk_put(chunk);
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}
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SCTP_DBG_OBJCNT_DEC(datamsg);
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kfree(msg);
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}
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/* Hold a reference. */
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static void sctp_datamsg_hold(struct sctp_datamsg *msg)
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{
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atomic_inc(&msg->refcnt);
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}
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/* Release a reference. */
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void sctp_datamsg_put(struct sctp_datamsg *msg)
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{
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if (atomic_dec_and_test(&msg->refcnt))
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sctp_datamsg_destroy(msg);
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}
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/* Assign a chunk to this datamsg. */
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static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk)
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{
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sctp_datamsg_hold(msg);
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chunk->msg = msg;
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}
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/* A data chunk can have a maximum payload of (2^16 - 20). Break
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* down any such message into smaller chunks. Opportunistically, fragment
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* the chunks down to the current MTU constraints. We may get refragmented
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* later if the PMTU changes, but it is _much better_ to fragment immediately
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* with a reasonable guess than always doing our fragmentation on the
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* soft-interrupt.
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*/
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struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
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struct sctp_sndrcvinfo *sinfo,
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struct msghdr *msgh, int msg_len)
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{
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int max, whole, i, offset, over, err;
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int len, first_len;
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int max_data;
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struct sctp_chunk *chunk;
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struct sctp_datamsg *msg;
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struct list_head *pos, *temp;
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__u8 frag;
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msg = sctp_datamsg_new(GFP_KERNEL);
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if (!msg)
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return ERR_PTR(-ENOMEM);
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/* Note: Calculate this outside of the loop, so that all fragments
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* have the same expiration.
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*/
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if (sinfo->sinfo_timetolive) {
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/* sinfo_timetolive is in milliseconds */
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msg->expires_at = jiffies +
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msecs_to_jiffies(sinfo->sinfo_timetolive);
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msg->can_abandon = 1;
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pr_debug("%s: msg:%p expires_at:%ld jiffies:%ld\n", __func__,
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msg, msg->expires_at, jiffies);
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}
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/* This is the biggest possible DATA chunk that can fit into
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* the packet
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*/
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max_data = asoc->pathmtu -
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sctp_sk(asoc->base.sk)->pf->af->net_header_len -
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sizeof(struct sctphdr) - sizeof(struct sctp_data_chunk);
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max = asoc->frag_point;
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/* If the the peer requested that we authenticate DATA chunks
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* we need to accound for bundling of the AUTH chunks along with
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* DATA.
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*/
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if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) {
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struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc);
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if (hmac_desc)
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max_data -= WORD_ROUND(sizeof(sctp_auth_chunk_t) +
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hmac_desc->hmac_len);
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}
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/* Now, check if we need to reduce our max */
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if (max > max_data)
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max = max_data;
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whole = 0;
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first_len = max;
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/* Check to see if we have a pending SACK and try to let it be bundled
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* with this message. Do this if we don't have any data queued already.
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* To check that, look at out_qlen and retransmit list.
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* NOTE: we will not reduce to account for SACK, if the message would
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* not have been fragmented.
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*/
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if (timer_pending(&asoc->timers[SCTP_EVENT_TIMEOUT_SACK]) &&
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asoc->outqueue.out_qlen == 0 &&
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list_empty(&asoc->outqueue.retransmit) &&
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msg_len > max)
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max_data -= WORD_ROUND(sizeof(sctp_sack_chunk_t));
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/* Encourage Cookie-ECHO bundling. */
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if (asoc->state < SCTP_STATE_COOKIE_ECHOED)
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max_data -= SCTP_ARBITRARY_COOKIE_ECHO_LEN;
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/* Now that we adjusted completely, reset first_len */
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if (first_len > max_data)
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first_len = max_data;
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/* Account for a different sized first fragment */
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if (msg_len >= first_len) {
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msg_len -= first_len;
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whole = 1;
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msg->can_delay = 0;
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}
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/* How many full sized? How many bytes leftover? */
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whole += msg_len / max;
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over = msg_len % max;
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offset = 0;
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if ((whole > 1) || (whole && over))
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SCTP_INC_STATS_USER(sock_net(asoc->base.sk), SCTP_MIB_FRAGUSRMSGS);
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/* Create chunks for all the full sized DATA chunks. */
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for (i=0, len=first_len; i < whole; i++) {
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frag = SCTP_DATA_MIDDLE_FRAG;
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if (0 == i)
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frag |= SCTP_DATA_FIRST_FRAG;
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if ((i == (whole - 1)) && !over) {
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frag |= SCTP_DATA_LAST_FRAG;
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/* The application requests to set the I-bit of the
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* last DATA chunk of a user message when providing
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* the user message to the SCTP implementation.
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*/
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if ((sinfo->sinfo_flags & SCTP_EOF) ||
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(sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY))
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frag |= SCTP_DATA_SACK_IMM;
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}
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chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0);
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if (!chunk) {
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err = -ENOMEM;
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goto errout;
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}
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err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov);
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if (err < 0)
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goto errout_chunk_free;
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offset += len;
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/* Put the chunk->skb back into the form expected by send. */
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__skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
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- (__u8 *)chunk->skb->data);
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sctp_datamsg_assign(msg, chunk);
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list_add_tail(&chunk->frag_list, &msg->chunks);
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/* The first chunk, the first chunk was likely short
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* to allow bundling, so reset to full size.
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*/
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if (0 == i)
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len = max;
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}
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/* .. now the leftover bytes. */
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if (over) {
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if (!whole)
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frag = SCTP_DATA_NOT_FRAG;
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else
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frag = SCTP_DATA_LAST_FRAG;
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if ((sinfo->sinfo_flags & SCTP_EOF) ||
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(sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY))
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frag |= SCTP_DATA_SACK_IMM;
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chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0);
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if (!chunk) {
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err = -ENOMEM;
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goto errout;
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}
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err = sctp_user_addto_chunk(chunk, offset, over,msgh->msg_iov);
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/* Put the chunk->skb back into the form expected by send. */
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__skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
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- (__u8 *)chunk->skb->data);
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if (err < 0)
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goto errout_chunk_free;
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sctp_datamsg_assign(msg, chunk);
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list_add_tail(&chunk->frag_list, &msg->chunks);
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}
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return msg;
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errout_chunk_free:
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sctp_chunk_free(chunk);
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errout:
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list_for_each_safe(pos, temp, &msg->chunks) {
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list_del_init(pos);
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chunk = list_entry(pos, struct sctp_chunk, frag_list);
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sctp_chunk_free(chunk);
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}
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sctp_datamsg_put(msg);
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return ERR_PTR(err);
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}
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/* Check whether this message has expired. */
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int sctp_chunk_abandoned(struct sctp_chunk *chunk)
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{
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struct sctp_datamsg *msg = chunk->msg;
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if (!msg->can_abandon)
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return 0;
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if (time_after(jiffies, msg->expires_at))
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return 1;
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return 0;
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}
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/* This chunk (and consequently entire message) has failed in its sending. */
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void sctp_chunk_fail(struct sctp_chunk *chunk, int error)
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{
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chunk->msg->send_failed = 1;
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chunk->msg->send_error = error;
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}
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